This invention is directed to a solder removal device.
There are known solder removal devices of varying forms such as the straight line pencil type described in U.S. Pat. No. 4,269,343 to Siegel, et al., the pistol grip type described in U.S. Pat. No. 3,842,240 to Wakita, et al. and numerous others in which the angle of the desoldering tip with respect to the handle is fixed in the range between 90.degree. and 180.degree.. In addition, many of these devices have finger-actuated switches on the hand pieces which generally operate the vacuum. Due to the fixed location of these switches, but more importantly the fixed angle between the desoldering tip and the handle, the operator's ability to alter hand positioning to suit individual preferences while simultaneously maintaining adequate control and proper positioning of the desoldering tip to the work is greatly limited.
Attempts have been made in the past to obviate similar hand positioning problems with regard to soldering irons with such adjustable devices as those disclosed in U.S. Pat. Nos. 1,519,246, and 1,928,522. However, the teachings of these patents cannot be successfully applied to desoldering devices due to the greater complexity thereof and the fundamental differences between desoldering and soldering.
Of primary importance in desoldering is the requirement that the desoldering tip must almost always assume a nearly exactly perpendicular position with respect to the work (typically a circuit board) in order to achieve an adequate seal so that molten solder can be aspirated completely, thereby freeing the solder joint. Tip positioning in soldering, although important, is not nearly as critical and the operator has much more flexibility in varying the tip position to suit his or her individual hand positioning requirements during soldering.
In addition, desoldering requires the frequent activation of a vacuum source which is often controlled by a switch on the desoldering handpiece itself. This therefore presents an additional hand positioning preference factor not present in soldering which also must be accomodated.
Finally, successful desoldering generally requires much greater control over the movement of the tip than is required in soldering because a component lead must be oscillated immediately before and during the actuation of the vacuum in order to allow the joint to cool down below the solder melt temperature and prevent the formation of a re-sweat joint.
The various desoldering devices mentioned above, with their varying configurations and angles, have not adequately addressed these problems and considerations inherent in desoldering.
Another problem common to these desoldering devices, especially those in which the molten aspirated solder must pass through angled passages and traverse a relatively great distance in order to reach the solder receptacle, is that of clogging. This results from a build-up of solder oxidation products and bits of solidified solder which do not remain in the liquid state long enough to reach the solder receptacle. Frequent clogging results in an inordinate amount of down time when the desoldering device must be cleaned. The cleaning of the device itself is hindered by angled passages of the solder path.
Still a further problem common to many of these desoldering devices is the overheating of the handle during continuous operation. This overheating not only presents a great discomfort to the operator but also could result in loss of efficiency and accuracy of work. Although this problem of overheating in part results from conduction and convection of hot air coming off of the heater element near the tip of the desoldering device, such overheating is also caused by the fact that the receptacle for the aspirated molten solder is contained within the hand piece itself.